fix: leader election stop deadlock (#1618)

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/Operator.java

@@ -67,7 +67,11 @@ public Operator(KubernetesClient kubernetesClient, ConfigurationService configur
 
   /** Adds a shutdown hook that automatically calls {@link #stop()} when the app shuts down. */
   public void installShutdownHook() {
-    Runtime.getRuntime().addShutdownHook(new Thread(this::stop));
+    if (!leaderElectionManager.isLeaderElectionEnabled()) {
+      Runtime.getRuntime().addShutdownHook(new Thread(this::stop));
+    } else {
+      log.warn("Leader election is on, shutdown hook will not be installed.");
+    }
   }
 
   public KubernetesClient getKubernetesClient() {
@@ -112,7 +116,6 @@ public void stop() throws OperatorException {
     final var configurationService = ConfigurationServiceProvider.instance();
     log.info(
         "Operator SDK {} is shutting down...", configurationService.getVersion().getSdkVersion());
-
     controllerManager.stop();
     ExecutorServiceManager.stop();
     leaderElectionManager.stop();

sample-operators/webpage/src/main/java/io/javaoperatorsdk/operator/sample/WebPageOperator.java

@@ -9,7 +9,8 @@
 import org.takes.http.Exit;
 import org.takes.http.FtBasic;
 
-import io.fabric8.kubernetes.client.*;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.client.KubernetesClientBuilder;
 import io.javaoperatorsdk.operator.Operator;
 
 public class WebPageOperator {